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International audience; The use of lignocellulosic biomass in the chemical industry has increased due to its non-competition with the food sector. Several platform molecules can be produced from this biomass. Among them, levulinic acid and its esters have been produced on an industrial scale. There are some reviews on the production of levulinic acid (LA) but few on the production of levulinates (LEs). To fill this gap, this review was written by also considering the environmental aspects. In the first stage, recent progress in the production of these platform chemicals was discussed. Production processes of alkyl levulinates from levulinic acid esterification, precursors (HMF, furfural, etc.), sugar monomers (glucose, fructose, etc.), cellulose, hemicellulose, or cellulose directly from lignocellulosic biomass were described. In the second stage, process separation and purification of LA and LEs were discussed. The final stage proposed an economic and environmental consideration for the production of these chemicals.

International audience; Biomass valorization to chemicals, biofuels or materials will be more and more important during this century. Production of γ-valerolactone (GVL) from the hydrogenation of levulinic acid is a good illustration of this tendency. GVL can also be produced from alkyl levulinates hydrogenation. Can we find a relationship between the structure and the kinetics of this reaction? Can we predict the kinetics of any alkyl levulinates by knowing the kinetics of another alkyl levulinate? This paper has studied these two questions by developing a kinetic model including the effect of gas-liquid mass transfer. We have demonstrated that the kinetics of hydrogenation of levulinic acid, methyl, ethyl and butyl levulinates to GVL using Ru/C follow the Taft equation, which is derived from Linear Free Energy Relationships. This equation measures the effects of polar and steric on a reaction series. We have demonstrated that polar effect of the reaction series is the most significant effect. This relationship can predict the values of kinetic constants just by knowing their structure.

International audience; The rapid progress of innovative biorefinery technologies raises the issue of emerging risk and major accident hazard in biorefineries, as process safety aspects of such technologies are not developing at the same pace with respect to their dissemination and scale-up.To address such problem, in the present work a consequence-based approach was integrated in the framework of a consolidated QRA methodology (ARAMIS), formerly developed in the context of Seveso Directive in the process industries (mainly oil&gas). Among all the possible scenarios identified using ARAMIS, Relevant Accident Scenarios (RAS) were selected by calculating hazard distances using threshold values for the evaluation of damages on human target derived from existing regulations on the control of major accident hazards.The method has been described and used to quantify the risk associated to a biorefinery process: the conversion of lignocellulosic biomass materials to levulinic acid and gamma-valerolactone, where the use of hazardous substances and severe process conditions are required.Using the proposed approach allowed to reduce the number of scenarios to be retained for further analysis. The RAS resulted 1/3 of the scenarios initially identified, simplifying the rest of the risk assessment procedure.The integrated methodology enabled to depict a risk figure for the plant analysed which is not over-conservative, being beneficial during the risk management phase, when risk reduction measures have to be selected and implemented in order to achieve risk tolerance.

The Canary Islands are still largely dependent on expensive imported fossil fuels, are stressed by the increasing touristic impact and are extremely vulnerable to climate change due to water scarcity. Water desalinisation is an energy-demanding process and is essential to the sustainable development of these islands. The aim of this study is to explore the potential advantages of a hybrid installation, exploiting two different renewable energy sources, specifically waves and solar, to supply a large desalination plant in Tenerife. The paper ultimately provides a generally applicable procedure for the design of hybrid installations, including three steps: the assessment of available renewable energy sources, the optimal combination of these sources and finally the economic assessment. The wave and solar resources are assessed first, then the hybrid installation is conceptually designed, proposing a criterion for the optimal mixing of the renewable energy sources that can be applied to other resources and other sites. The basic idea is to maximise the exploitation of the renewable power, minimizing the need of the fossil-based back-up system. The costs of the hybrid installation are finally assessed considering the sensitivity to government incentives, showing that the project parity point is reached within the lifetime of typical desalination plants (i.e. 40 years) and can be significantly more attractive in case of Feed-In-Tariffs available in other European countries.

With more than 350 GWh per year and thousands of installations around the world, biogas is an appealing strategy in the field of energy production and industrial waste optimization. In this sense, it is of paramount importance to address the risk associated with such plants, as an increasing trend of accidents have been recorded in the last 20 years. In this work, a representative biogas production plant was considered, and a risk assessment was carried out through the combination of Recursive Operability Analysis and Failure Mode and Effects Criticality Analysis. The methodology is rigorous and allows for both the identification and the quantification of accidental scenarios due to procedural errors and equipment failures, which miss in the literature for the case of biogas. The analysis allows the automatic generation of the Fault Trees for the identified Top Events, which can be numerically solved. Results show that the most critical accidental scenario in the biogas plant here considered is the formation of an explosive air-biogas mixture, which can occur in both anaerobic digester and condensate trap. The calculated probabilities agree with the results available in literature on similar plants. Pumps and Distributed Control System were found to be the most critical components.

One of the most common but promising processes for the production of paints and coatings is the free radical emulsion polymerization reaction involving different types of monomers. As it is also demonstrated by statistics concerning accidents in chemical industries, polymerizations are one of the most frequent causes of thermal runaway; therefore such syntheses require a very high level of control of all the operating variables, especially at full plant scale where safety problems are of paramount importance. The main aims of this work were the modeling and the industrial scale optimization of a complex polymerization process. Since four different monomers are involved in different proportions in such a process, the pseudo-homopolymer approach together with available literature correlations for the estimation of the main constitutive parameters of the system were used to solve the mathematical model and simulate the dynamics of the synthesis at the full plant scale. The proposed model and all the constitutive parameters estimates were validated through the comparison with both laboratory and full-scale experimental data, demonstrating a good agreement. Finally, the results of the optimization procedure were validated at laboratory scale.

Industrial infrastructures, in particular those where hazardous substances are stored or handled, may be the target of malicious acts aiming at the disruption of normal operations. In the present study a toolbox of complementary and synergic techniques (Correspondence Analysis (CA), Fishbone Diagrams, Cause-Consequence Chains, Adversary Sequence Diagram, Root Cause Analysis) was applied to the in-depth analysis of physical security- and cybersecurity-related events that affected the process industry. The unprecedented original set of information obtained provides novel insights concerning these events. Clear correlations among security threats, including cyber-threats, and specific industrial sectors, as well as among the final scenarios and the different security threats from which they originate were identified by CA. In particular, vandalism resulted strongly correlated with the transportation of hazardous substances, and theft of materials with oil and gas pipelines. When considering chemical and petrochemical sites, cyber-attacks and the use of improvised explosives resulted to be the most common attack modes performed by the threat actors. Personnel and vehicle gateways resulted key elements when designing the Physical Protection System (PPS) of a facility. Insiders having the permission to enter the site bypass such controls, and were responsible of several successful attacks. Overall, the results confirm the concreteness of security-related events in the process industry and provide an original structured and detailed insight on the attack patterns experienced to date. Moreover, the results and the data obtained provide a novel set of baseline information for the application of SVA (Security Vulnerability Assessment) or SRA (Security Risk Assessment) methodologies in facilities where hazardous substances are stored or processed.

Security threats are becoming an increasing concern for chemical sites and related infrastructures where relevant quantities of hazardous materials are processed, stored or transported. In the present study, security related events that affected chemical and process sites, and related infrastructures, were investigated. The aim of the study is to frame a clear picture of the threats affecting the chemical and process industry, and to issue lessons learnt from past events. A database of 300 security-related accidents was developed and populated, starting from European and American sources. Threat categories that caused such events were identified and analyzed. The attack modes were investigated. Important differences were found with respect to geographical areas and industrial sectors affected. The use of explosives (both military and improvised explosive devices) is by far the more frequent attack mode, although armed attacks and arson are also frequent events and may result in an in-depth penetration of the attackers. In recent years, cyber-attacks are also posing important threats. Lessons learnt call for the implementation of a specific security management system in the chemical and process industry, aiming at the physical and cyber protection of industrial sites.

Summary In the formulation of acrylic coatings, monomer blends are required to cure in situ using a peroxide initiator. Curing accelerators (typically alkyl anilines) are added to the blend in order to initiate the curing process at room temperature. This was proved to cause a process safety issue related to the presence of accelerators that increase the possibility of runaway reactions especially at industrial scale. In this paper, the polymerization of methyl methacrylate containing different curing accelerators has been studied. Based on Differential Scanning Calorimetry tests, a simplified kinetic model for the polymerization process has been developed, describing the induction time due to the presence of stabilizers, the global kinetic rate, and the influence of diffusion phenomena, based on a free volume theory approach specifically modified for the free radical polymerization of methyl methacrylate added with different types of accelerators.

In the last 10 years biogas production tripled, resulting in an increasing number of related facilities. The present study addresses safety issues of such activity on the basis of past accident analysis. A database of accidents related to biogas supply chain was created and data on 169 accidents were collected from different literature sources. Trends, causes of accidents, scenarios, and consequences were analysed also using Multi Correspondence Analysis to obtain correlations between causes of accidents and scenarios. The study showed that almost 12% of the past accident analysed can be classified as major accidents. The number of accidents is growing faster than biogas production. A risk assessment was carried, based on the analysis of accident frequencies and consequences. A non-negligible risk profile, typical of ALARP zone, was obtained for this industrial sector, revealing an emerging risk issue. The main lessons learnt are the need of developing and adopting specific safety standards and of improving the safety culture and risk awareness in the biogas production sector.

Biogas is becoming an increasingly important resource of energy production from biomass, and a number of alternative technologies are proposed for its production and upgrading. However, in spite of the increasing number of accidents recorded, scarce attention was dedicated to date to the control and mitigation of biogas hazards. In this study, inherent safety of biogas technologies was addressed. A method for the selection of inherently safer alternatives during early design stages was further developed and combined to a Monte Carlo sensitivity analysis, accounting for uncertainty of input parameters and addressing the robustness of the ranking provided. The method was applied to the assessment of several alternative reference process schemes for biogas production and upgrading. The results allowed the identification of critical safety issues and the ranking of inherently safer solutions. © 2016 American Institute of Chemical Engineers AIChE J, 62: 2713–2727, 2016

In recent years bioprocesses are becoming a cornerstone of the production industry and have been implemented for large scale production. Despite its importance, the safety of such processes has not been yet systematically analyzed and studied. The hazards of biotechnological processes entail both conventional chemical process hazards and biohazards related to the presence of microorganisms. In the present study a specific methodology for hazard identification in biotechnological processes has been developed, aimed at the integrated assessment of conventional hazards and biohazards at industrial scale. The potentialities and outcome of the methodology were tested by its application to the anaerobic digestion of animal manure for biogas production, which represents a widespread bioprocess for energy production from renewable sources.

Biogas production is growing worldwide. At European level, biogas is among the renewable energy sources whose exploitation is progressing more. Important investments are planned in biogas upgrading facilities for the production of biomethane. The relevant increase in biogas production raises emerging risk issues associated to biogas facilities. In order to systematically explore the hazards related to biogas production and upgrading, a specific methodology (DyPASI - Dynamic Procedure for Hazard Identification) was applied. Despite the great variety of existing plants and components, it was possible to identify reference critical events and cause-consequence chains. The results were used to identify a set of safety barriers for accident prevention and mitigation in biogas production and upgrading facilities.

The use of biomass as feedstock to produce chemicals or biofuels is increasing. This renewable, biodegradable and ecofriendly feedstock could present some new risks that should be taken into account. In this context, a thermal risk assessment of levulinic acid (LA) hydrogenation to γ-valerolactone (GVL), which is a platform molecule produced from lignocellulosic biomass process, catalyzed by Ru/C in water was performed. A kinetic model including an energy balance under near-adiabatic conditions was built. For that, different experiments at different operating conditions (levulinic acid concentration and catalyst loading) were performed by using an Advanced Reactive System Screening Tool (ARSST) to estimate the kinetic constants of this reaction system. To make a thermal risk assessment of a chemical reaction system, two safety parameters should be defined: Time-to-Maximum Rate under adiabatic conditions (TMRad) and adiabatic temperature rise (ΔTad). The parameter TMRad defines the time to reach the maximum temperature rate and characterizes the probability of risk. The parameter ΔTad is the difference between the maximum and initial reaction temperature and characterizes the severity of risk. Based on this kinetic model, these two parameters were determined at different operating conditions. With the aid of a risk matrix, it was possible to determine the safe operating conditions (temperature, levulinic acid concentration, hydrogen pressure and catalyst loading).

The interest in the epoxidation of vegetable oils is constantly growing in the chemical industry. The most common process is based on the oxidation of the unsaturated bonds by peroxyacids generated in situ, in the water phase, using concentrated hydrogen peroxide and the corresponding organic acid in presence of a mineral acid as catalyst. The overall epoxidation reaction is highly exothermic, hence operating conditions should be always addressed by safety considerations related to the possibility of runaway reactions. In this paper, best operating conditions and safety considerations have been defined for a complex reaction network for the epoxidation of soybean oil, which includes the decomposition reactions of the performic acid generated during the epoxidation. Furthermore, sensitivity-based reactor stability criteria have been applied and compared, for the design of an adequate Early Warning Detection System for the process.

Low-thermal inertia experiments in the open cell configuration were carried out to perform a comprehensive sensitivity analysis of the parameters affecting the runaway self-decomposition of dicumyl peroxide (DCP). This study facilitates a better understanding on how concentration, initial back pressure, and fill level influence DCP runaway severity. The outcome of this experimental study was compared to previous adiabatic closed cell experiments, with the aim of clarifying the discrepancies reported in the literature and contributing to essential knowledge about self-decomposing peroxide systems. Results showed that the detected onset temperature, maximum temperature, maximum pressure, and time to maximum rate are affected by the configuration of the equipment and initial back pressure of the experiments, while the adiabatic temperature rise did not seem to be affected. The roles that the kinetics, fluid dynamics, and thermodynamics play on these observations is addressed and discussed through the manuscript.